Twilight 2000 is a role playing game set in the aftermath of World War III. The premise is that the United States and the Soviet Union have gone to (limited) nuclear war with all its consequences. The game was first published during the Cold War and was intended to be a accurate depiction of a possible future, but events in the world have rendered the premise of the game an alternate history. The scenarios in Twilight 2000 typically involve a military unit which was stranded in Central Europe after the nuclear war and places emphasis on attempting to realistically depict military and social systems after a nuclear war.

The manufacturer of the game, Game Designers Workshop, which is now owned by Tantalus, has combined the timelines of Twilight 2000 with the science fiction games 2300 AD, by doing so the rather depressing post-nuclear environment of Twilight 2000 is mitigated by the outcome in which the Earth rebuilds itself and begins to colonize space.